12S25 Mt Vesuvius



Mount Vesuvius is an active composite volcano/stratovolcano that lies in the Campanian volcanic arc in the Gulf of Naples, Italy. It is the only volcano on the European mainland to have erupted within the last hundred years. (Last eruption: 1944)

Rich supply of magma
Mount Vesuvius sits on top of a thick layer of magma deep in the earth that measures around 400 square kilometers. Comparing its magma supply to that of the Kilaeua Volcano's, (probably the most active volcano in the world with 34 eruptions since 1952), it greatly surpasses the amount of magma that the Kilaeua Volcano has.

Evacuation plan
The Italian government has devised an evacuation plan to clear out the red zone 72 hours ahead of an impending eruption. Starting from 2004, the government has also set up a program to pay people $46,000 (30,000E) to relocate outside of the red zone -- though it has had relatively few takers.

Short term
An estimated 16,000 citizens in the Roman vicinities of Pompeii and Herculaneum perished due to hydrothermal pyroclastic flows at temperatures up to 700 °C (1292 °F). A precursor, the Avellino eruptiopn in the Bronze Age, deposited about 0.32 km3 of white pumice, while a second, more intense explosion raised a column of 31 km (102,000 ft) depositing 1.25 km3 of grey pumice ("the grey pumice phase"); however, the 79 eruption produced a rain of pumice southward of the cone that built up to depths of 2.8 metres (9 ft 2 in) at Pompeii.

The eruption of Vesuvius in 79 unfolded in two phases, a Plinian eruption that lasted eighteen to twenty hours, followed by a pyroclastic flow in the second, Pelean phase that reached as far as Misenum but was concentrated to the west and northwest. Two pyroclastic flows engulfed Pompeii, burning and asphyxiating the stragglers who had remained behind. Oplontis and Herculaneum received the brunt of the flows and were buried in fine ash and pyroclastic deposits.

Long term
Mount Vesuvius is best known for its eruption in AD 79 that led to the burying and destruction of the Roman cities of Pompeii and Herculaneum. They were never rebuilt, although surviving townspeople and probably looters did undertake extensive salvage work after the destructions. The towns' locations were eventually forgotten until their accidental rediscovery in the 18th century.

The eruption also changed the course of the Sarno River and raised the sea beach, so that Pompeii was now neither on the river nor adjacent to the coast. Vesuvius itself underwent major changes – its slopes were denuded of vegetation and its summit changed considerably due to the force of the eruption. Vesuvius has erupted many times since and is today regarded as one of the most dangerous volcanoes in the world because of the population of 3,000,000 people living nearby and its tendency towards explosive (Plinian) eruptions. It is the most densely populated volcanic region in the world.